Differences in the Sublethal Effects of Sulfoxaflor and Acetamiprid on the Aphis gossypii Glover (Homoptera: Aphididae) Are Related to Its Basic Sensitivity Level

SIMPLE SUMMARY: The sublethal effects of insecticides are not only environmentally risky to arthropods but may also promote resistance evolution. Sublethal effects are influenced by factors such as the type of insecticide, sublethal concentration, and type of pest. This study evaluated the sublethal effects of sulfoxaflor and acetamiprid on two field cotton aphid (Aphis gossypii) populations with different genetic backgrounds. For acetamiprid, a significant negative sublethal effect of an LC(25) concentration of acetamiprid on longevity and fecundity was observed in the F(0) generation of Jinghe, and a significant negative sublethal effect occurred in the F(1) and F(2) generations of Yarkant, some biological traits of which were significantly degraded. However, in terms of biological traits, significant stimulative sublethal effects of an LC(25) concentration of sulfoxaflor were observed in the F(0) generation of Jinghe and the F(1) generation of Yarkant. These experimental results demonstrate that sulfoxaflor and acetamiprid have different sublethal effects on A. gossypii that vary depending on the generation. Moreover, the sublethal effects of an insecticide may be influenced by the genetic background and resistance levels of A. gossypii. Our findings are useful for assessing the overall effects of sulfoxaflor and acetamiprid on A. gossypii. ABSTRACT: The cotton aphid, Aphis gossypii, is an important insect pest of many crops around the world, and it has developed resistance to a large number of frequently used insecticides. The sublethal effects of insecticides not only have an environmental risk to arthropods but also have the potential to promote resistance evolution. The sublethal effects (inhibitory or stimulatory) are influenced by many factors, such as the type of insecticide, sublethal concentrations, pest species, and others. In this study, the sublethal effects of sulfoxaflor and acetamiprid on A. gossypii were compared using two field-collected populations. The results show that sulfoxaflor was more toxic than acetamiprid against A. gossypii in both populations, the LC(50) concentrations of acetamiprid and sulfoxaflor were 6.35 and 3.26 times higher, respectively, for the Jinghe population than for Yarkant. The LC(25) concentration of acetamiprid significantly reduced adult longevity and fecundity in exposed adults (F(0)) of the Jinghe population, but it had no significant effects on these factors in Yarkant. Similar inhibitory effects were found in the F(1) and F(2) generations, but the biological traits in the Yarkant population were significantly reduced when the parents (F(0)) were exposed to LC(25) of acetamiprid, whereas the changes in the Jinghe population were not significant. However, sublethal sulfoxaflor showed a stimulatory effect on A. gossypii in the F(0) and F(1) generation; the adult fecundity and longevity of the F(0) generation were significantly higher in Jinghe, while the biological traits of the F(1) generation were obviously higher in Yarkant. In the F(2) generation, the r and λ were significantly higher in Jinghe; meanwhile, these biological traits were reduced in Yarkant. These results indicate that sulfoxaflor and acetamiprid had different sublethal effects on A. gossypii that varied by generation. In addition, we speculate that the genetic background and the resistance levels of A. gossypii may also influence the sublethal effects. Our findings are useful for assessing the overall effects of sulfoxaflor and acetamiprid on A. gossypii.